The present invention relates to a loader control device for controlling a loader which carries out a delivery of works to an outer machine such as machine tools.
According to an automatic machine tool of NC lathe or the like, a loader is attached to the machine tool main body, and the work is transported in and out automatically. In the loader of gantry loader or the like, there are several important locating positions during the operation of a series of a cycle. For example:
a. load/unload position to the spindle chuck,
b. load/unload position to the work reversing machine,
c. delivering position between other transporting device.
Generally, the setting of these positions are carried out by a professional operator in advance to the starting of mass production, by a so-called work, xe2x80x9cinstructionxe2x80x9d, and is handled as a fixed position during mass production.
However, during mass production, there are cases in which the locating fails even by forcibly appointing to the position by using the fixed value, due to various changes in the condition, such as a mechanic saccadic movement, deterioration of the mechanism parts, and changes in the material differentiation. For example, there are cases in which it leads to a breakdown or an accident wherein it proceeds to processing under impossible posture wherein defective articles are produced, and a work falls off from the chuck or the like during processing. In some cases, the breakdown can be prevented beforehand by stopping the abnormal load alarm of the loader axis, and defects generate in that the operating rate decreases.
It is thus an object of the present invention to provide a loader control device capable of preventing the generation of abnormal operation of the loader or the delivery mistakes due to the core displacement of the chuck when delivering a work to the chuck of an outer device.
It is another object of the present invention to facilitate the adjustment of the work delivering position just by changing the coordinates.
It is still a further object of the present invention to prevent the abnormality reflecting on the next processing when an abnormality generates.
The present invention will now be described in reference to FIG. 1 which corresponds to the embodiment. A loader control device is a loader control device 20 for controlling a loader 5 which delivers a work W to a chuck 2 of an outer device 1. Moreover, the loader control device comprises a displaced amount detecting means 31 and an adjusting means 32. The displaced amount detecting means 31 detects by the torque of the motors 11, 12 of the loader 5, the displacement of a center position of a loader chuck 14 and a center position of the chuck 2 of the outer device 1, when a work W is delivered with the loader chuck 14 placed on the work delivering position. The adjusting means 32 adjusts the work delivering position of the loader chuck 14 by an amount corresponding to the detected displaced amount when delivering the next work W.
According to this structure, the position of the loader chuck 14 is fixed to the work delivering position instructed beforehand, and the work W is delivered to the chuck 2 of the outer device 1. When the work W is held by the chuck 2 of the outer device 1 and becomes under a restricted state, in the case a displacement has occurred between the center position of the loader chuck 14 and the center position of the chuck 2 of the outer device 1, the torque of the motors 11, 12 for transferring the chuck position of the loader 5 increases. The displaced amount detecting means 31 detects the displacement of the center position of the loader chuck 14 and the center position of the chuck 14 of the outer device 1, by the torque under the restricted state. The adjusting means 32 adjusts the work delivering position of the loader chuck 14 by the amount corresponding to the displaced amount detected by the displaced amount detecting means 31 when delivering the next work W. Therefore, even when a displacement is generated in the appropriate work delivering position due to various changing factors from the time the work delivering position is instructed, the work W can be delivered by adjusting the displacement constantly. As a result, the abnormal operation of the loader or the delivering failure due to the displacement in the core of the chucks 2, 14 can be prevented from generating. Further, the adjusting amount can be the same as the displaced amount or can be in a predetermined ratio to the displaced amount.
Moreover, the outer device 1 mentioned here is a device different from the loader 5, and for example, when the loader 5 is embedded inside the machine tool of the lathe or the like, the outer device 1 can be a section other than the loader in the machine tool. The chuck 2 of the outer device 1 is a chuck of the device delivered with a work W from the loader 5.
According to the present invention, the loader 5 operates by the coordinate data of the work delivering position appointed by the loader program 21, and can carry out an adjustment of the work delivering position by either rewriting the coordinate data or adding revised amount based on aforementioned displaced amount. The specification of the work delivering position by the loader program 21 is carried out by the identifying code {circle around (1)}, {circle around (2)}, {circle around (3)} . . . of the work delivering position, and the coordinate data corresponding to the identifying code can be stored in the locating position setting means 23, and the work delivering position can be specified by the coordinate data directly to the loader program 21.
In either case, based on the detected displaced amount, by rewriting the coordinate data or by adding the revised amount, the adjusting of the work delivering position can be carried out easily. When storing the coordinate data to the locating position setting means 23, the rewriting of the coordinate data based on the displaced amount is to be for example, rewriting the stored coordinate data itself. When writing the coordinate data to the processing program 21, for example, the coordinate data of the processing program 21 is to be rewritten. When adding the revised amount based on the displaced amount, for example, revising can be added when outputting the operational command by the coordinate data set in the locating position setting means 23 or in the processing program.
According to the present invention, when the torque of the motors 11, 12 is larger than the set value, a processing means during excess load 33 for stopping the adjustment of the delivering position by the adjusting means 32 can be provided.
When the torque of the motors 11, 12 is excessive, it can be assumed that some abnormality, exceeding tolerance level, has occurred. In such case, the adjustment of the delivering position by the adjusting means 32 is stopped, and the abnormality in the adjustment is prevented by the processing means during excess load 33. The judgment whether or not the torque of the motor is larger than the set value can be carried out after converting the torque of the motor into the displaced amount. Moreover, the process to stop the adjustment by the adjusting means 32 can be made not to carry out the adjusting process accordingly, by stopping the displaced amount being input to the adjusting means 32.
Further, according to the present invention, a correlation setting means 34 which sets the correlation of the motor torque and the displaced amount can be provided, and the displaced amount detecting means 31 can figure out the displaced amount by referring the detected torque to the correlation setting means 34.
As in the manner stated above, by providing the correlation setting means 34, the displaced amount can be instantly found from the torque value.